GCP Pub/Sub Destination¶

Stream Keycloak events to Google Cloud Pub/Sub.

Property	Value
`destination.kind`	`gcp-pubsub`
Protocol	HTTP/REST (Pub/Sub API)

Compatible Systems¶

System	Notes
Google Cloud Pub/Sub	Fully managed, global messaging service
GCP Pub/Sub Emulator	Local development and testing

Example Configurations¶

GCP Pub/Sub (Service Account)GCP Pub/Sub (Base64 Credentials)GCP Pub/Sub (Inline Credentials)GCP Pub/Sub EmulatorWith Ordering Key

kete.routes.pubsub.destination.kind=gcp-pubsub
kete.routes.pubsub.destination.project=my-gcp-project
kete.routes.pubsub.destination.topic=keycloak-events
kete.routes.pubsub.destination.credentials-file-path=/secrets/service-account.json

kete.routes.pubsub.destination.kind=gcp-pubsub
kete.routes.pubsub.destination.project=my-gcp-project
kete.routes.pubsub.destination.topic=keycloak-events
kete.routes.pubsub.destination.credentials-file-base64=ewogICJ0eXBlIjogInNlcnZpY2VfYWNj...

kete.routes.pubsub.destination.kind=gcp-pubsub
kete.routes.pubsub.destination.project=my-gcp-project
kete.routes.pubsub.destination.topic=keycloak-events
kete.routes.pubsub.destination.credentials-file-text={"type":"service_account","project_id":"my-gcp-project",...}

kete.routes.pubsub.destination.kind=gcp-pubsub
kete.routes.pubsub.destination.project=demo-project
kete.routes.pubsub.destination.topic=keycloak-events
kete.routes.pubsub.destination.url=http://pubsub-emulator:8085
# No credentials needed for emulator

kete.routes.pubsub.destination.kind=gcp-pubsub
kete.routes.pubsub.destination.project=my-gcp-project
kete.routes.pubsub.destination.topic=keycloak-events
kete.routes.pubsub.destination.credentials-file-path=/secrets/service-account.json
kete.routes.pubsub.destination.ordering-key=keycloak

Features¶

Google Cloud Pub/Sub REST API integration (no GCP SDK required)
Service account authentication with automatic OAuth 2.0 token management
Three credential loading methods (file path, inline text, Base64)
Emulator support for local development and testing
Topic templating with variables
Message ordering key support
Event metadata sent as Pub/Sub message attributes
Custom user-defined Pub/Sub message attributes
TLS/mTLS support

Configuration Properties¶

Required Properties¶

Property	Description	Example
`destination.kind`	Must be `gcp-pubsub`	`gcp-pubsub`
`destination.project`	GCP project ID	`my-gcp-project`
`destination.topic`	Pub/Sub topic name (supports templating)	`keycloak-events`

Optional Properties¶

Property	Default	Description	Example
`destination.url`	`https://pubsub.googleapis.com`	Pub/Sub REST API base URL (override for emulators)	`http://localhost:8085`
`destination.timeout-seconds`	`10`	HTTP request and connect timeout in seconds	`30`
`destination.ordering-key`	(empty)	Ordering key for all published messages (supports templating)	`keycloak`
`destination.authentication-type`	(empty)	Authentication method (see Authentication)	`service-account-file-path`

Dynamic Properties (Templating)¶

The topic and ordering-key properties support template variables:

# Dynamic topic per realm
kete.routes.pubsub.destination.topic=keycloak-events-${realmLowerCase}

# Dynamic topic per event type
kete.routes.pubsub.destination.topic=keycloak-${eventTypeLowerCase}

# Dynamic ordering key
kete.routes.pubsub.destination.ordering-key=${realmLowerCase}

Available variables: ${realmLowerCase}, ${realmUpperCase}, ${realmKebabCase}, ${realmPascalCase}, ${realmCamelCase}, ${eventTypeLowerCase}, ${eventTypeUpperCase}, ${eventTypeKebabCase}, ${eventTypePascalCase}, ${eventTypeCamelCase}, ${kindLowerCase}, ${kindUpperCase}, ${kindKebabCase}, ${kindPascalCase}, ${kindCamelCase}, ${resourceTypeLowerCase}, ${resourceTypeUpperCase}, ${resourceTypeKebabCase}, ${resourceTypePascalCase}, ${resourceTypeCamelCase}, ${operationTypeLowerCase}, ${operationTypeUpperCase}, ${operationTypeKebabCase}, ${operationTypePascalCase}, ${operationTypeCamelCase}, ${resultLowerCase}, ${resultUpperCase}, ${resultKebabCase}, ${resultPascalCase}, ${resultCamelCase}

Message Attributes¶

Every published message includes these Pub/Sub message attributes automatically:

Attribute	Description	Example
`eventkind`	Whether it's a user event or admin event	`EVENT`, `ADMIN_EVENT`
`eventtype`	The Keycloak event type	`LOGIN`, `USER_CREATE`
`contenttype`	MIME type of the message body	`application/json`

Custom Attributes¶

Custom attributes can be added to Pub/Sub messages using the headers.* prefix:

kete.routes.pubsub.destination.headers.source=keycloak
kete.routes.pubsub.destination.headers.environment=production

These are forwarded as Pub/Sub message attributes alongside the built-in attributes above. The 3 built-in attributes always take priority on key conflict.

Authentication (Credentials)¶

GCP Pub/Sub uses service account credentials for authentication. Set destination.authentication-type and provide credentials using the corresponding method:

Authentication Type	Required Property	Description
`service-account-file-path`	`destination.credentials-file-path`	Filesystem path to a GCP service account JSON file
`service-account-file-text`	`destination.credentials-file-text`	GCP service account JSON provided inline as plain text
`service-account-file-base64`	`destination.credentials-file-base64`	GCP service account JSON provided as a Base64-encoded string
`application-default`	(none)	Uses Application Default Credentials (ADC)

Emulator Mode

Credentials are not required when using the GCP Pub/Sub Emulator. Set destination.url to the emulator endpoint (e.g., http://localhost:8085) and omit all credential properties.

Credential Validation

If destination.url is the default (https://pubsub.googleapis.com), at least one credential property must be set. Using the emulator URL without credentials is allowed.

How Authentication Works¶

KETE reads the service account JSON (containing client_email and private_key)
Creates a signed JWT (RS256) with scope https://www.googleapis.com/auth/pubsub
Exchanges the JWT at Google's token endpoint for an OAuth 2.0 access token
Caches and automatically refreshes the access token
Includes the access token as a Bearer token in all Pub/Sub API requests

TLS Properties¶

See TLS & mTLS for full details on TLS options.

Property	Default	Description
`destination.tls.enabled`	`false`	Enable TLS
`destination.tls.key-store.*`	-	Client certificate for mTLS
`destination.tls.trust-store.*`	-	CA certificates

Google Cloud Pub/Sub TLS

When connecting to the real Google Cloud Pub/Sub service (https://pubsub.googleapis.com), TLS is handled automatically via HTTPS — no explicit TLS configuration needed. TLS properties are useful when connecting through a proxy or custom endpoint.

Configuration Examples¶

Example 1: Production Setup¶

kete.routes.prod.destination.kind=gcp-pubsub
kete.routes.prod.realm-matchers.realm=list:master
kete.routes.prod.event-matchers.filter=glob:*
kete.routes.prod.destination.project=my-production-project
kete.routes.prod.destination.topic=keycloak-events
kete.routes.prod.destination.authentication-type=service-account-file-path
kete.routes.prod.destination.credentials-file-path=/secrets/service-account.json
kete.routes.prod.destination.timeout-seconds=30
kete.routes.prod.destination.ordering-key=keycloak

Example 2: Per-Realm Topics¶

# Production realm events
kete.routes.prod-events.destination.kind=gcp-pubsub
kete.routes.prod-events.realm-matchers.realm=list:production
kete.routes.prod-events.event-matchers.filter=glob:*
kete.routes.prod-events.destination.project=my-gcp-project
kete.routes.prod-events.destination.topic=prod-keycloak-events
kete.routes.prod-events.destination.authentication-type=service-account-file-path
kete.routes.prod-events.destination.credentials-file-path=/secrets/service-account.json

# Development realm events
kete.routes.dev-events.destination.kind=gcp-pubsub
kete.routes.dev-events.realm-matchers.realm=list:development
kete.routes.dev-events.event-matchers.filter=glob:*
kete.routes.dev-events.destination.project=my-gcp-project
kete.routes.dev-events.destination.topic=dev-keycloak-events
kete.routes.dev-events.destination.authentication-type=service-account-file-path
kete.routes.dev-events.destination.credentials-file-path=/secrets/service-account.json

Example 3: Local Development with Emulator¶

kete.routes.local.destination.kind=gcp-pubsub
kete.routes.local.realm-matchers.realm=list:master
kete.routes.local.event-matchers.filter=glob:*
kete.routes.local.destination.project=demo-project
kete.routes.local.destination.topic=keycloak-events
kete.routes.local.destination.url=http://localhost:8085

Example 4: Kubernetes with Base64 Credentials¶

# Credentials injected as env var from Kubernetes secret
kete.routes.k8s.destination.kind=gcp-pubsub
kete.routes.k8s.realm-matchers.realm=list:master
kete.routes.k8s.event-matchers.filter=glob:*
kete.routes.k8s.destination.project=my-gcp-project
kete.routes.k8s.destination.topic=keycloak-events
kete.routes.k8s.destination.authentication-type=service-account-file-base64
kete.routes.k8s.destination.credentials-file-base64=${GCP_SA_KEY_BASE64}

Quick Starts¶

Quick Start	Description
gcp-pubsub	Google Cloud Pub/Sub (real cloud)
gcp-pubsub-emulator	GCP Pub/Sub Emulator (local)